About the Event

Establishing patterns of susceptibility to fatigue and fracture in the Mn/DOT bridge inventory can help estimate future spending and rehabilitation needs. Details in steel bridges that are sensitive to fatigue and fracture can be enumerated and rated by their overall frequency and consequence of fracture.

The research conducted includes a review of case studies and predictive formulas for fatigue and fracture, as well as a timeline of changes to applicable bridge code provisions. Historic cases of cracking from fatigue and fracture were gathered, and the frequency of occurrence was defined by means of a national survey of departments of transportation. The result is a classification system expressed as a comprehensive table correlating geometric constraints to rank numbers for eighteen common steel bridge details that are possible locations for fatigue or fracture cracking. A computer program was developed that can be used to calculate a composite rank number from the classification system for each bridge based upon distribution and rank of the individual details present in the bridge.

An effort is currently ongoing to implement this classification scheme for the ranking of the approximately 1000 steel bridges in the Minnesota trunk highway system.